Encapsulation of haloalkane 1-(3-chlorophenyl)-4-(3-chloropropyl)-piperazinium in symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril

Abstract

Complexation of haloalkane 1-(3-chlorophenyl)-4-(3-chloropropyl)-piperazinium (PZ⁺) dihydrochloride with symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril (TMeQ[6]) has been investigated using NMR spectroscopy, MALDI-TOF mass spectrometry, isothermal titration calorimetry (ITC), and X-ray crystallography. Our data indicate that the chloropropyl group of PZ⁺ resides within the cavity of TMeQ[6] in both aqueous solution and the solid state, generating a highly stable inclusion complex PZ⁺@TMeQ[6]. In aqueous solution, the formation of the inclusion complex PZ⁺@TMeQ[6] benefits from the ion–dipole interactions between the guest PZ⁺ and the host TMeQ[6]. While in the solid state, hydrogen-bonding interactions also play an important role in stabilizing the inclusion complex PZ⁺@TMeQ[6].